Small differences in nucleic acid sequences can result in significant differences in biological function. In the diagnostic context, single nucleotide polymorphisms (SNPs) in the human genome underlie differences in susceptibility to disease. A wide range of human diseases, such as sickle-cell anemia, β-thalassemia, Alzheimer's and cystic fibrosis result from SNPs.
In other contexts, single nucleotide mutations can be effective for gene therapy or synthetic biology. In gene therapy approaches a single nucleotide change can provide a healthy version of a gene that when introduced to a patient's cells will treat a disease that is caused by a mutant version of the gene. Synthetic biology can create industrially useful bio-molecules based on mutations, even at a single nucleotide site, in the nucleic acids that encode them.
The ability to capture or select a nucleic acid having a desired SNP or mutant is useful for characterization, synthesis, and quality assessment of nucleic acids in many contexts such as the diagnostic, therapeutic and synthetic approaches exemplified above. In many situations the desired sequences are in low abundance and/or present in a background of contaminants such as other nucleic acids having different sequences. Current methods exploit the specificity of binding between complementary nucleic acid strands for such capture and selection. In a typical technique, a target nucleic acid is captured using a support-bound nucleic acid that is complementary to the sequence of the target nucleic acid. Although, complementarity is theoretically capable of distinguishing sequences, in practical terms many samples are highly complex with regard to the variety of non-target sequences present and with regard to the sheer number of non-target molecules compared to target molecule. Such complexity makes it impractical and in some cases improbable to selectively capture a sequence that differs from contaminating nucleic acids by only one or a few nucleotides.
Thus, there exists a need for methods to separate nucleic acids that differ from each other by only a few or even only one nucleotide. The present disclosure satisfies this need and provides related advantages as well.